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41.
主要对MBR技术处理生活污水的效果进行分析研究。MBR技术因用膜分离代替二沉池而节约了占地面积,而且MBR系统对污水中的COD、NH3-H有较高的去除率,而对浊度的去除更显示了其优越性,出水浊度几乎为零,大大提高系统出水的水质,且整个系统的出水具有很强的稳定性,面对原污水中COD、NH3-H的波动较大,MBR系统显示了较强的抗冲击负荷。虽然MBR技术是一种新型的水处理技术,但鉴于其在处理行业的优越性,因而应用前景较广。 相似文献
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新型污泥减量技术研究 总被引:1,自引:0,他引:1
从现阶段剩余污泥的处理与处置投资大、成本高的现状出发,分析了实际污泥减量化的几种污水处理技术,提出了一种以生物砾石为微生物载体的新型污水处理技术,其不仅具有良好的处理效果,而且达到了无剩余污泥排放的目标。 相似文献
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45.
Tiago Natal-da-Luz Serena Tidona Bruno Jesus Paula V. Morais José P. Sousa 《Journal of Soils and Sediments》2009,9(3):246-260
Background, aim, and scope Sewage sludge use in agriculture should be limited by the presence of metals and other persistent environmental pollutants.
The present study aims to contribute for the definition of a test battery of ecotoxicological assays that allows a proper
ecotoxicological characterization of sludges, providing information on their potential hazard and identified “safe” application
levels.
Materials and methods Three sludges from distinct sources (urban, olive-processing, and electroplating industries) were tested using avoidance and
reproduction tests with earthworms (Eisenia andrei) and springtails (Folsomia candida) and plant growth tests with turnips (Brassica rapa) and oats (Avena sativa). Different soil–sludge mixture concentrations mimicking recommended/realistic field dosages were tested.
Results Only the sludge from the electroplating industry induced an avoidance response from the earthworms (EC50 = 0.4 t/ha) and collembolans (no observed effect concentration (NOEC) = 15 t/ha). This sludge was the only sludge responsible
for any effect on the reproductive output of the earthworms (EC50 = 7.74 t/ha). Regarding collembolans, none of the sludges tested caused any significant decrease in reproduction. In higher
plant tests, the two industrial sludges were toxic, causing a decrease growth in both species. The EC20 values determined for B. rapa were 20.3 and 24.2 t/ha and for A. sativa 14.7 and 16.2 t/ha for sludges from olive-processing and electroplating industries, respectively.
Discussion The metal loadings of the different test sludges could partially explain the results obtained. The toxicity of the test sludge
from electroplating industry observed on the tested invertebrates and plants could be explained by the high amount of total
chromium from which 22.3% was in the most toxic oxidation state—Cr(VI). However, the toxicity caused by the sludge from the
olive-processing industry in the test plants could be attributed to the presence of other compounds (not measured in this
study) since the metal content was not high enough to induce such an effect. The absence of toxicity showed by the urban test
sludge was in agreement with its low levels of metals.
Conclusions The response of the different test organisms and end points varied according to the sludge type. The urban sludge was non-toxic
whereas the sludge from the electroplating industry caused a toxic effect on almost all parameters measured (avoidance behavior
of both test organisms, reproduction of earthworms, and growth of both plant species). Sludge from the olive-processing industry
only caused a toxic effect on growth of both plant species. By analyzing the sensitivity of the different parameters for the
most toxic sludge, it was found that avoidance and reproduction were more sensitive than plant growth, whereas plant seed
germination was not sensitive at all.
Recommendations and perspectives The ecotoxicological evaluation of wastes can be used as an environmental safety control of sludge use in agriculture. A tiered
approach could be adopted for this purpose, incorporating avoidance tests in the first tier (screening level) and reproduction
and plant growth tests in a second tier. But more evidence aiming to define the most suitable ecotoxicological test battery
for specific sludges with a different contamination profile is still needed. 相似文献
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47.
ABSTRACT Previous research has shown that supplying adequate sulfur (S) continuously in combination with reduced amounts of nitrogen (N) will produce a quality plant. However, not all commercially available fertilizers use the same source of S, contain the same or optimal concentration of it, or contain any S at all. Additionally, nutrient incompatibility can occur if all the macronutrients are combined in one solution or one dry fertilizer. Thus, the objective of this research was to determine the effect of different methods of application and different types of S fertilizers on chrysanthemum growth. Two experiments were conducted in which three S sources (H2SO4, MgSO4, and K2SO4) were applied in combination with three N concentrations (50, 100, and 150 mg L?1) as fertilizer treatments. Sulfur was applied at 10 mg L?1, either continuously—by slightly acidulating the fertilizer solution with H2SO4—or in one, two, or three single, discrete applications as either K2SO4 or MgSO4. Leaf N concentration was greatest when 100 or 150 mg N L?1 was applied. As expected, S applied continuously by slightly acidulating the fertilizer solution with sulfuric acid resulted in higher leaf S concentration and larger flower diameter than under any of the other treatments. Together, plants fertilized with S continuously at 10 mg S L?1 and N at 100 mg L?1 were the largest, had the largest flower diameter, and contained the greatest leaf N and S concentrations. Sulfur concentration in the mix was highest and N concentration lowest when S was supplied continuously. Thus, if growers need to supply S and acidulate their water, sulfuric acid would be the best choice. If there are concerns about possible S contamination in landfills or in mix recycling, either potassium or magnesium S, applied multiple times as single applications in combination with 100 or 150 mg N L?1, may be a better choice. 相似文献
48.
城市污泥有机肥对马铃薯产量、品质及重金属吸收的影响 总被引:1,自引:1,他引:0
通过大田试验初步探讨了污泥有机肥对马铃薯的增产效应及其对马铃薯品质、重金属吸收的影响。结果表明,在施化肥的基础上,施用污泥有机肥可显著提高马铃薯产量、等级和品质;施用污泥有机肥的马铃薯薯块中Hg、As、Pb、Cd、Cr、Cu和Zn含量均在国家食品卫生标准范围内。 相似文献
49.
Study on the Pretreatment Technology of Phosphogypsum 总被引:1,自引:0,他引:1
The economic and effective pretreatment is a key to its recycling into useful building materials. The pretreatment such as washing, neutralizing with quick lime, grinding, floating, screening, calcination etc. have been studied. The effectiveness, problems and feasibility of pretreatment are analyzed. This paper presents the pretreatment principle of phosphogypsum utilization. If the phosphogypsum utilized is more than hundred thousand tones per year, the washing technology is recommended, otherwise, the technology of neutralizing with quick lime and grinding should be chosen. 相似文献
50.
污泥土地利用的风险与控制 总被引:2,自引:0,他引:2
介绍了污泥土地利用中重金属污染、病原体和寄生虫污染、有机物污染和氮磷污染的各种风险及控制,提出了污泥土地利用中存在的问题和解决的对策。 相似文献